[mythtv-users] XvMC channel change freezes front-end

Brad Templeton brad+myth at templetons.com
Thu Dec 2 20:09:06 UTC 2004

> No, this is the age-old "XvMC doesn't work" problem. 
> The OSD causes the frontend to freeze hard when using
> XvMC.  In other cases it only causes severe
> stuttering.  I fixed the problem by buying a more
> powerful CPU and motherboard so I could use Xv.  So
> far that is the only guaranteed fix for this problem.

Well, it's not XcMC's fault, in that if you run mplayer with
xvmc (on an nvidia on a RH9 system, I will admit to not having xvmc
working on my FC3 :-), it works quiet smoothly, with low CPU, and as I
recall with clean OSD and certainly with window overlay.  Clean,
instananeous seeks (no pixelation) etc.

So somewhere in mplayer's output drivers is the answer to reliable

Demand for xvmc will probably pick up in spite of moore's law
making it easier to do it all in xv.    I see two pushes in
a home-built PVR:

    a) HDTV -- even with a 3ghz system, you're pushing the edges
    with pure HD.  I get about 20-30% idle but it's very easy
    for a task to come along and take you to zero and stutter your
    video.  With xvmc you are at about 60% idle, and could in fact
    run on those super cheap systems now available based on things
    like a Sempron 2500.  (One sees Sempron 2500 plus motherboard
    for about $70 around here.)

    b) Repurposing obsolete computers.  We all have old sub-ghz
    machines sitting around.   You can get Geforce4 cards for $30
    and that will continue to drop.  It makes a lot of sense to
    repurpose these as non-HD Mythboxes, since otherwise you would
    throw them out!   A winpvr-350 is another approach, reportedly
    also problematic.  But a 350 is about $170, which is more than
    the value of the old machine.  On the other hand, once drivers
    appear for the $80 wintv-150 it makes more sense.

More information about the mythtv-users mailing list